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Title: Improvements In Ethanologenic Escherichia Coli and Klebsiella Oxytoca

The current Verenium cellulosic ethanol process is based on the dilute-acid pretreatment of a biomass feedstock, followed by a two-stage fermentation of the pentose sugar-containing hydrolysate by a genetically modified ethanologenic Escherichia coli strain and a separate simultaneous saccharification-fermentation (SSF) of the cellulosic fraction by a genetically modified ethanologenic Klebsiella oxytoca strain and a fungal enzyme cocktail. In order to reduce unit operations and produce a fermentation beer with higher ethanol concentrations to reduce distillation costs, we have proposed to develop a simultaneous saccharification co-fermentation (SScF) process, where the fermentation of the pentose-containing hydrolysate and cellulosic fraction occurs within the same fermentation vessel. In order to accomplish this goal, improvements in the ethanologens must be made to address a number of issues that arise, including improved hydrolysate tolerance, co-fermentation of the pentose and hexose sugars and increased ethanol tolerance. Using a variety of approaches, including transcriptomics, strain adaptation, metagenomics and directed evolution, this work describes the efforts of a team of scientists from Verenium, University of Florida, Massachusetts Institute of Technology and Genomatica to improve the E. coli and K. oxytoca ethanologens to meet these requirements.
Authors:
Publication Date:
OSTI Identifier:
992134
Report Number(s):
DOEGO17058
TRN: US201022%%387
DOE Contract Number:
FC36-07GO17058
Resource Type:
Technical Report
Research Org:
Verenium Corporation
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; BIOMASS; DISTILLATION; ENZYMES; ESCHERICHIA COLI; ETHANOL; FERMENTATION; HEXOSES; KLEBSIELLA; PENTOSES; SACCHARIDES; SACCHARIFICATION; STRAINS; TOLERANCE